The Terms of Service clearly indicated that all content that you provide to SO Inc is licensed under CC-BY-SA, and that would include your About Me section of your user profile, which SO Inc is actively modifying, without indication, to remove links to a community fundraiser.
You agree that any and all content, including without limitation any and all text, graphics, logos, tools, photographs, images, illustrations, software or source code, audio and video, animations, and product feedback (collectively, “Content”) that you provide to the public Network (collectively, “Subscriber Content”), is perpetually and irrevocably licensed to Stack Overflow on a worldwide, royalty-free, non-exclusive basis pursuant to Creative Commons licensing terms (CC-BY-SA).
Currently, SO Inc insists that all content is now CC-BY-SA 4.0, which means that all modifications must be indicated.
In the 4.0 license suite, licensees are required to indicate if they made modifications to the licensed material. This obligation applies whether or not the modifications produced adapted material. As with all other attribution and marking requirements, this may be done in a manner reasonable to the means, medium, and context. For example, "This section is an excerpt of the original." For trivial modifications, such as correcting spelling errors, it may be reasonable to omit the notice.
Full legal text:
Section 3 – License Conditions. Your exercise of the Licensed Rights is expressly made subject to the following conditions. a.Attribution. 1. If You Share the Licensed Material (including in modified form), You must: A. retain the following if it is supplied by the Licensor with the Licensed Material: i. identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any reasonable manner requested by the Licensor (including by pseudonym if designated); ii. a copyright notice; iii. a notice that refers to this Public License; iv. a notice that refers to the disclaimer of warranties; v. a URI or hyperlink to the Licensed Material to the extent reasonably practicable; B. indicate if You modified the Licensed Material and retain an indication of any previous modifications; and C. indicate the Licensed Material is licensed under this Public License, and include the text of, or the URI or hyperlink to, this Public License. 2. You may satisfy the conditions in Section 3(a)(1) in any reasonable manner based on the medium, means, and context in which You Share the Licensed Material. For example, it may be reasonable to satisfy the conditions by providing a URI or hyperlink to a resource that includes the required information. 3. If requested by the Licensor, You must remove any of the information required by Section 3(a)(1)(A) to the extent reasonably practicable.
So where does Stack Overflow get the right to modify licensed content without indicating changes?